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@Book{            book:872605,
  Author        = "Marek, Wiktor and Onyszkiewicz, Janusz",
  date-added    = "2023-02-06 13:29:34 +0100",
  date-modified = "2023-02-06 13:29:43 +0100",
  ISBN          = "9027710848,9789027710840,9027721319,9789027721310",
  Publisher     = "D.Reidel",
  Title         = "Elements of logic and foundations of mathematics in problems",
  URL           = "http://gen.lib.rus.ec/book/index.php?md5=6401639aa6f1853fa3ce7baeba08c00e",
  Year          = "1982",
  bdsk-url-1    = "http://gen.lib.rus.ec/book/index.php?md5=6401639aa6f1853fa3ce7baeba08c00e",
  File          = "Elements of logic and foundations of mathematics in problems.pdf",
  file-2        = "Elements of logic and foundations of mathematics in problems.djvu"
}

@Book{ book:872605, Author = "Marek, Wiktor and Onyszkiewicz, Janusz", date-added = "2023-02-06 13:29:34 +0100", date-modified = "2023-02-06 13:29:43 +0100", ISBN = "9027710848,9789027710840,9027721319,9789027721310", Publisher = "D.Reidel", Title = "Elements of logic and foundations of mathematics in problems", URL = "http://gen.lib.rus.ec/book/index.php?md5=6401639aa6f1853fa3ce7baeba08c00e", Year = "1982", bdsk-url-1 = "http://gen.lib.rus.ec/book/index.php?md5=6401639aa6f1853fa3ce7baeba08c00e", File = "Elements of logic and foundations of mathematics in problems.pdf", file-2 = "Elements of logic and foundations of mathematics in problems.djvu" }